@aws-cdk/assert

Testing utilities and assertions for CDK libraries

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This is a developer preview (public beta) module. Releases might lack important features and might have future breaking changes.

This API is still under active development and subject to non-backward compatible changes or removal in any future version. Use of the API is not recommended in production environments. Experimental APIs are not subject to the Semantic Versioning model.

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This library contains helpers for writing unit tests and integration tests for CDK libraries

Unit tests

Write your unit tests like this:

const stack = new Stack();

new MyConstruct(stack, 'MyConstruct', {
    ...
});

expect(stack).to(someExpectation(...));

Here are the expectations you can use:

Verify (parts of) a template

Check that the synthesized stack template looks like the given template, or is a superset of it. These functions match logical IDs and all properties of a resource.

matchTemplate(template, matchStyle)
exactlyMatchTemplate(template)
beASupersetOfTemplate(template)

Example:

expect(stack).to(beASupersetOfTemplate({
    Resources: {
        HostedZone674DD2B7: {
            Type: "AWS::Route53::HostedZone",
            Properties: {
                Name: "test.private.",
                VPCs: [{
                    VPCId: { Ref: 'VPC06C5F037' },
                    VPCRegion: { Ref: 'AWS::Region' }
                }]
            }
        }
    }
}));

Check existence of a resource

If you only care that a resource of a particular type exists (regardless of its logical identifier), and that some of its properties are set to specific values:

haveResource(type, subsetOfProperties)

Example:

expect(stack).to(haveResource('AWS::CertificateManager::Certificate', {
    DomainName: 'test.example.com',
    // Note: some properties omitted here

    ShouldNotExist: ABSENT
}));

ABSENT is a magic value to assert that a particular key in an object is not set (or set to undefined).

Check number of resources

If you want to assert that n number of resources of a particular type exist, with or without specific properties:

countResources(type, count)
countResourcesLike(type, count, props)

Example:

expect(stack).to(countResources('AWS::ApiGateway::Method', 3));
expect(stack).to(countResourcesLike('AWS::ApiGateway::Method', 1, {
  HttpMethod: 'GET',
  ResourceId: {
    "Ref": "MyResource01234"
  }
}));

Check existence of an output

haveOutput assertion can be used to check that a stack contains specific output. Parameters to check against can be:

• outputName
• outputValue
• exportName

If outputValue is provided, at least one of outputName, exportName should be provided as well

Example

expect(synthStack).to(haveOutput({
  outputName: 'TestOutputName',
  exportName: 'TestOutputExportName',
  outputValue: {
    'Fn::GetAtt': [
      'TestResource',
      'Arn'
    ]
  }
}));

Changelog

1.25.0 (2020-02-18)

⚠ BREAKING CHANGES TO EXPERIMENTAL FEATURES

• appsync: Changes MappingTemplate.dynamoDbPutItem() to accept PrimaryKey and AttributeValues, which allow configuring the primary key and to project an object to a set of attribute values.

Features

• appsync: more general mapping template for DynamoDB PutItem (#6236) (e9937d3), closes #6225
• aws-applicationautoscaling: support Lambda and Comprehend (#6191) (bdab747)
• cfn: update CloudFormation spec to v11.0.0 (#6311) (ea272fa)

Bug Fixes

• aws-lambda-nodejs: Fix parcel invocation when invoked from globally installed cdk cli (#6206) (ce96e08), closes #6204
• codepipeline: fixed typo in method docs within action.ts (78a39b7)
• eks: Helm release name length & --wait option. (#6276) (1811e00), closes /github.com/helm/helm/blob/b63822ed12de1badbb61736d2f7ea4e756ef757d/pkg/action/install.go#L52-L55
• lambda-nodejs: not meaningful parcel error message when build fails (#6277) (a97b48a), closes #6274